Study on the difference of numbing substances in different Zanthoxylum germplasm resources

The numbing sensation serves as one of the important indicators for evaluating the quality of Zanthoxylum plants. In this study, pericarp samples from 113 Zanthoxylum accessions of different geographical origins were selected as the research object, the main numbing substances (hydroxyl-ε-sanshool, hydroxyl-α-sanshool, hydroxyl-γ-sanshool, and hydroxyl-β-sanshool) were qualitatively and quantitatively analyzed by high-performance liquid chromatography (HPLC). In addition, cluster analysis and principal component analysis (PCA) were employed to decipher the compositional characteristics and content variations of numbing compounds across different origins. The results showed that there were significant differences in the composition patterns and contents of pungent substances among different geographical sources and varieties of Zanthoxylum. Longitude was extremely significantly negatively correlated with the content of hydroxy-γ-sanshool, and a larger longitude led to a smaller content of hydroxy-γ- sanshool, which was lower than the content of hydroxy-ε-sanshool it contains, thus changing the composition characteristics of the pungent substances of Zanthoxylum. Altitude was extremely significantly positively correlated with the total content of pungent substances. In areas with higher altitude, the content of pungent substances in Zanthoxylum was also higher. Hydroxy-α-sanshool accounted for the highest proportion in the total numbing substances, serving as the primary contributor to the characteristic numbing sensation. Notably, Hanyuanhuajiao exhibited distinct differentiation due to their significantly elevated levels of hydroxyl-γ-sanshool. This study systematically elucidated the compositional characteristics and quantitative differences of numbing substances in Zanthoxylum plants, which provided scientific basis for the selection of superior varieties and enriched the research framework on the chemical substances responsible for its characteristic numbing sensation of Zanthoxylum plants.